Unequal-ratio Ce doped pyrochlore and fluorite double-phase high-entropy rare earth zirconate thermal barrier coating material and preparation method thereof

Abstract

The invention relates to the technical field of thermal barrier coating materials, in particular to an unequal-ratio Ce doped pyrochlore and fluorite double-phase high-entropy rare earth zirconate thermal barrier coating material and a preparation method thereof. The chemical composition formula of the thermal barrier coating material provided by the invention is (La < 0.2 > Ce < 0.1 > Sm < 0.1 > Dy < 0.2 > Yb < 0.2 > Sc < 0.2 >) < 2 > Zr < 2 > O < 7 >, (La < 0.2 > Sm < 0.2 > Yb < 0.2 > Sc < 0.2 > Y < 0.1 > Ce < 0.1 >) < 2 > Zr < 2 > O < 7 >, and (La < 0.2 > Ce < 0.1 > Nd < 0.1 > Yb < 0.2 > Lu < 0.2 > Sc < 0.2 >) < 2 > Zr < 2 > O < 7 >. The thermal expansion performance of the prepared coating material is obviously improved under the conditions that the low thermal conductivity, the high mechanical property and the high sintering resistance are met at the same time, and therefore the high-entropy rare earth zirconate thermal barrier coating material of the Ce-containing double-phase structure is promoted, and it is guaranteed that the material is practically applied to the field of thermal barrier coating materials.

Description

Technical Field

[0001] This invention relates to the field of thermal barrier coating materials, and more particularly to non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating materials and their preparation methods. Background Technology

[0002] Thermal barrier coatings are heat-insulating materials used on the surface of turbine blade alloy substrates in aero-engines or internal combustion engines. They isolate the alloy component substrate from high-temperature combustion gases, reducing the alloy substrate temperature, improving engine thermal efficiency (over 60%), and extending service life. Currently widely used 8YSZ coatings undergo phase transformation and sintering at service temperatures above 1200℃, failing to meet the requirements of next-generation high thrust-to-weight ratio aero-engines. High-temperature phase stability is one of the fundamental properties for novel thermal barrier coating ceramic materials to replace traditional YSZ ceramic materials.

[0003] A2B2O7 rare-earth zirconates with a single-phase structure of pyrochlore or defective fluorite possess low thermal conductivity, a large coefficient of thermal expansion, and high-temperature phase stability, making them the most promising alternative to 8YSZ thermal barrier coating ceramic materials. However, the thermal expansion properties, sintering resistance, and mechanical properties of single-phase rare-earth zirconate thermal barrier coating ceramic materials still limit their application in the field of thermal barrier coatings. To alleviate thermal stress concentration caused by the mismatch in the coefficients of thermal expansion of the thermal barrier coating, which leads to coating peeling, the most effective measure is to maximize the coefficient of thermal expansion of the ceramic layer and minimize the difference in linear expansion coefficients between it and the binder layer. Furthermore, to improve the stress-strain tolerance of the thermal barrier coating ceramic layer and avoid coating failure caused by various stress concentrations, the ceramic layer should possess high hardness, low elastic modulus, and high fracture toughness. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating material and its preparation method, which possesses excellent high-temperature phase stability, low thermal conductivity, low elastic modulus, high coefficient of thermal expansion, high hardness and fracture toughness, and excellent anti-sintering properties.

[0005] The non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare-earth zirconate thermal barrier coating material of the present invention has the chemical formula (La... 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7、(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce0.1 )2Zr2O7、(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 One of )2Zr2O7.

[0006] The preparation method of the non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating material of the present invention includes the following steps: S1, the rare earth source and zirconium source are respectively arranged according to (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7、(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7、(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 A solution is prepared by mixing ingredients in a molar ratio of one of the molecular formulas in 2Zr2O7. S2, using the reverse coprecipitation method, the solution obtained in step S1 is added dropwise to ammonia water while continuously stirring; S3. After the flocculent precipitate obtained in step S2 has been left to stand and age for a period of time, it is then centrifuged, washed, and dried. S4. The dried mixed powder obtained in step S3 is preheated for a period of time to obtain a mixed heat-treated powder. The preheated mixed powder is sintered in a muffle furnace for a period of time to obtain a rare earth zirconate thermal barrier coating powder.

[0007] Furthermore, during the reverse coprecipitation titration in step S2, ammonia water needs to be continuously added to control the pH to always be greater than 10, ensuring that flocculent precipitate is completely generated.

[0008] Furthermore, in step S3, the settling and aging time is no less than 24 hours to ensure that the materials react fully and allow the flocculated suspended matter to settle.

[0009] Furthermore, in step S3, the generated flocculent precipitate is first washed repeatedly by centrifugation with deionized water until neutral, and then washed twice each with ethanol and isopropanol.

[0010] Furthermore, in step S4, the preheating temperature is 950~1100 °C, and the preheating time is 5~10 h.

[0011] Furthermore, in step S4, sintering is carried out in an air atmosphere in a muffle furnace at a calcination temperature of 1350~1600 ℃ for at least 6 h.

[0012] Furthermore, the rare earth source includes one of rare earth oxides, rare earth chlorides, rare earth nitrates, and rare earth sulfates.

[0013] Furthermore, the zirconium source includes one of zirconium dichloride octahydrate, zirconium nitrate, zirconium sulfate, and zirconium chloride.

[0014] This invention utilizes calculations based on atomic size difference and radius ratio to prepare a novel non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare-earth zirconate thermal barrier coating material. The non-uniformly doped material exhibits excellent high-temperature phase stability, exhibiting no phase transformation during long-term high-temperature service; lower thermal conductivity; smaller grain size and a very slow growth rate, resulting in excellent resistance to sintering; and significantly improved mechanical properties such as hardness, elastic modulus, fracture toughness, and coefficient of thermal expansion.

[0015] Compared to the low coefficient of thermal expansion and mechanical properties of undoped Ce-containing pyrochlore and fluorite dual-phase rare-earth zirconate thermal barrier coatings, Ce-doped pyrochlore and fluorite dual-phase rare-earth zirconate thermal barrier coatings significantly improve the coefficient of thermal expansion and mechanical properties (hardness, elastic modulus, and fracture toughness) of dual-phase high-entropy rare-earth zirconate thermal barrier coatings while simultaneously achieving low thermal conductivity and high anti-sintering performance. This improved overall performance of dual-phase high-entropy rare-earth zirconates effectively extends the service life of materials and promotes the practical application of dual-phase high-entropy rare-earth zirconate materials in the field of thermal barrier coatings. Attached Figure Description

[0016] Figure 1 In Example 1 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc0.2 X-ray diffraction pattern of 2Zr2O7(FPC3) biphase high-entropy rare earth zirconate sintered at 1600 °C for 10 h; Figure 2 In Example 2 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 The thermal expansion coefficient of 2Zr2O7(FPC3) dual-phase high-entropy rare earth zirconate varies with temperature; Figure 3 In Example 3 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 X-ray diffraction pattern of 2Zr2O7(FPC3) biphase high-entropy rare earth zirconate sintered at 1350 °C for 6 h; Figure 4 In Example 3 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 Mechanical properties of 2Zr2O7(FPC3) dual-phase high-entropy rare earth zirconate: Hardness (HV), Elastic modulus (E), Fracture toughness (K). IC ); Figure 5 In Comparative Example 1 (La) 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 X-ray diffraction pattern of 2Zr2O7(FP3) biphase high-entropy rare earth zirconate sintered at 1600 °C for 10 h; Figure 6 In Comparative Example 2 (La) 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 The thermal expansion coefficient of 2Zr2O7(FP3) dual-phase high-entropy rare earth zirconate varies with temperature; Figure 7 In Comparative Example 3 (La) 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 X-ray diffraction pattern of 2Zr2O7(FP3) biphase high-entropy rare earth zirconate sintered at 1350 °C for 6 h; Figure 8 In Comparative Example 3 (La) 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 Mechanical properties of 2Zr2O7(FP3) dual-phase high-entropy rare earth zirconate: Hardness (HV), Elastic modulus (E), Fracture toughness (K). IC ); Figure 9 It is in Example 4 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 )2Zr2O7(FPC3) and Comparative Example 4 (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 Comparison of grain size variation trends of 2Zr2O7(FP3) dual-phase high-entropy rare earth zirconate; Figure 10 In Example 3 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 )2Zr2O7(FPC3) and Comparative Example 3 (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 Comparison of high-temperature thermal expansion coefficients of 2Zr2O7(FP3) dual-phase high-entropy rare earth zirconates; Figure 11 In Comparative Example 5, the single-phase high-entropy (Ce) 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2Yb 0.2 )2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 X-ray diffraction pattern of 2Zr2O7(F3) sintered at 1350 °C for 6 h; Figure 12 This is the single-phase high-entropy (Ce) in Comparative Example 5. 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 Statistical results and growth trend of average grain size of 2Zr2O7(F3). Detailed Implementation

[0017] The following are specific embodiments of the present invention. The technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

[0018] Example 1 (1) Based on the chemical composition formula: (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7,(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7,(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2One of the following Zr₂O₇ compounds is used: Rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃, respectively, are dissolved in nitric acid to form a rare earth nitrate solution; CeCl₃ and ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ and Ce 3+ Solution.

[0019] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated in a high-temperature sintering furnace at 1100 °C for 5 h; the heat-treated powder was sintered in a high-temperature sintering furnace at 1600 °C for 10 h to obtain FPC1, FPC2, and FPC3 pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating materials, respectively.

[0020] Example 2 (1) Based on the chemical composition formula: (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7,(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7,(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 One of the following Zr₂O₇ compounds is used: Rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃, respectively, are dissolved in nitric acid to form a rare earth nitrate solution; CeCl₃ and ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ and Ce3+ Solution.

[0021] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated at 950 °C for 10 h in a high-temperature sintering furnace; the heat-treated powder was pressed into a long rod of 5 mm * 5 mm * 25 mm in a stainless steel mold and sintered at 1600 °C for 10 h in a high-temperature sintering furnace to obtain a long rod-shaped block sample of pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating for thermal expansion coefficient testing.

[0022] The two-phase structure of pyrochlore and fluorite (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 The thermal expansion coefficients of the high-entropy rare-earth zirconate thermal barrier coating material 2Zr2O7(FPC3) are 11.38, 11.41, and 11.61 × 10⁻⁶, respectively. -6 K -1 (Ambient temperature ~ 1500°C).

[0023] Example 3 (1) Based on the chemical composition formula: (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7,(La 0.2 Sm 0.2 Yb0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7,(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 One of the following Zr₂O₇ compounds is used: Rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃, respectively, are dissolved in nitric acid to form a rare earth nitrate solution; CeCl₃ and ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ and Ce 3+ Solution.

[0024] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated in a high-temperature sintering furnace at 950 °C for 5 h; then sintered in the high-temperature sintering furnace at 1350 °C for 6 h to obtain a two-phase (La) mixture. 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 )2Zr2O7(FPC3) powder.

[0025] The biphase powder obtained in step (4) was loaded into a high-strength graphite mold and sintered in a discharge plasma sintering furnace (SPS) at a pressure of 40 MPa and a temperature of 1500 °C for 5 min. After grinding and decarburization, a dense biphase rare earth zirconate thermal barrier coating block sample was obtained and its thermal conductivity and mechanical properties were tested.

[0026] The two-phase structure of pyrochlore and fluorite (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 The high-entropy rare-earth zirconate thermal barrier coating material 2Zr2O7(FPC3) exhibits low thermal conductivity, ranging from 1.68 to 1.43 W·m. -1 K -1 1.75~1.56 W·m -1 K -1 1.50~1.30 W·m -1 K -1 (Room temperature ~1500 °C).

[0027] It exhibits high hardness (15.01, 16.53, 15.04 GPa), low elastic modulus (230.93, 237.85, 222.43 GPa), and high fracture toughness (1.66, 1.56, 1.78 MPa·m). 1 / 2 ).

[0028] Example 4 (1) Based on the chemical composition formula: (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7,(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1)2Zr2O7,(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 One of the following Zr₂O₇ compounds is used: Rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃, respectively, are dissolved in nitric acid to form a rare earth nitrate solution; CeCl₃ and ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ and Ce 3+ Solution.

[0029] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated in a high-temperature sintering furnace at 950 °C for 10 h; the heat-treated powder was pressed into a circular disc with a diameter of 12 mm in a stainless steel mold and sintered in a high-temperature sintering furnace at 1600 °C for 10, 30, 50, 70 and 100 h respectively to obtain circular block samples of pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating for sintering resistance testing.

[0030] The two-phase structure of pyrochlore and fluorite (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 The average grain sizes of 2Zr2O7 (FPC1) were 1.19, 1.66, 1.93, 2.09, and 2.28 μm, respectively; (La) 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 The average grain sizes of 2Zr2O7 (FPC2) were 1.08, 1.54, 1.81, 1.98, and 2.13 μm, respectively; (La) 0.2 Ce 0.1 Nd 0.1 Yb0.2 Lu 0.2 Sc 0.2 The average grain sizes of 2Zr2O7 (FPC3) are 0.91, 1.19, 1.37, 1.58, and 1.76 μm, respectively.

[0031] Comparative Example 1: (1) Based on the chemical composition formula: (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 One of Zr₂O₇(FP₃) is prepared by dissolving rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃ from a specific chemical formula in dilute nitric acid to form a rare earth nitrate solution; ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ Solution.

[0032] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) is preheated at 1100 °C for 5 h in a high-temperature sintering furnace; the heat-treated powder is sintered at 1600 °C for 10 h in a high-temperature sintering furnace to obtain a dual-phase high-entropy rare earth zirconate thermal barrier coating material of pyrochlore and fluorite.

[0033] Comparative Example 2 (1) Based on the chemical composition formula: (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 One of Zr₂O₇(FP₃) is prepared by dissolving rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃ from a specific chemical formula in dilute nitric acid to form a rare earth nitrate solution; ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ Solution.

[0034] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated at 950 °C for 10 h in a high-temperature sintering furnace; the heat-treated powder was pressed into a long rod of 5 mm * 5 mm * 25 mm in a stainless steel mold and sintered at 1600 °C for 10 h in a high-temperature sintering furnace to obtain a long rod-shaped block sample of pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating for thermal expansion coefficient testing.

[0035] The two-phase structure of pyrochlore and fluorite (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2The thermal expansion coefficients of the Zr₂O₇(FP₃) high-entropy rare-earth zirconate thermal barrier coating materials are 10.97, 10.94, and 11.08 × 10⁻⁶, respectively. -6 K -1 (Ambient temperature ~1500 °C).

[0036] Comparative Example 3 (1) Based on the chemical composition formula: (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 One of Zr₂O₇(FP₃) is prepared by dissolving rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃ from a specific chemical formula in dilute nitric acid to form a rare earth nitrate solution; ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ Solution.

[0037] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated in a high-temperature sintering furnace at 950 °C for 5 h; then sintered in the high-temperature sintering furnace at 1350 °C for 6 h to obtain a two-phase (La) mixture. 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 )2Zr2O7(FP3) powder.

[0038] The biphase powder obtained in step (4) was loaded into a high-strength graphite mold and sintered in a discharge plasma sintering furnace (SPS) at a pressure of 40 MPa and a temperature of 1500 °C for 5 min. After grinding and decarburization, a dense biphase rare earth zirconate thermal barrier coating block sample was obtained and its thermal conductivity and mechanical properties were tested.

[0039] The two-phase structure of pyrochlore and fluorite (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 The low thermal conductivity of the 2Zr2O7(FP3) high-entropy rare earth zirconate thermal barrier coating material is 1.80~1.40 W·m. -1 K -1 1.86~1.62 W·m -1 K -1 1.64~1.25 W·m -1 K -1 (Room temperature ~1500 °C).

[0040] Hardness (16.63, 17.00, 16.57 GPa), elastic modulus (239.77, 241.72, 227.12 GPa), and poor fracture toughness (1.31, 1.17, 1.40 MPa·m) 1 / 2 ).

[0041] Comparative Example 4 (1) Based on the chemical composition formula: (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 One of Zr₂O₇(FP₃) is prepared by dissolving rare earth oxides La₂O₃, Nd₂O₃, Sm₂O₃, Dy₂O₃, Yb₂O₃, Lu₂O₃, Sc₂O₃, and Y₂O₃ from a specific chemical formula in dilute nitric acid to form a rare earth nitrate solution; ZrOCl₂ 8H2O dissolves in deionized water to form Zr 4+ Solution.

[0042] (2) Add the mixed solution obtained in step (1) dropwise to ammonia water with pH>10.0, and keep the pH>10 throughout the process while stirring continuously to generate flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried mixed powder obtained in step (4) was preheated in a high-temperature sintering furnace at 950 °C for 10 h; the heat-treated powder was pressed into a circular disc with a diameter of 12 mm in a stainless steel mold and sintered in a high-temperature sintering furnace at 1600 °C for 10, 30, 50, 70 and 100 h respectively to obtain circular block samples of pyrochlore and fluorite dual-phase high-entropy rare earth zirconate thermal barrier coating for sintering resistance testing.

[0043] The two-phase structure of pyrochlore and fluorite (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 The average grain sizes of 2Zr2O7 (FP1) were 1.25, 1.69, 1.95, 2.21, and 2.49 μm, respectively; (La) 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 The average grain sizes of 2Zr2O7(FP2) are 1.37, 1.85, 2.24, 2.38, and 2.71 μm, respectively; (La) 0.2 Nd 0.2 Yb 0.2 Lu0.2 Sc 0.2 The average grain sizes of 2Zr2O7(FP3) are 0.97, 1.27, 1.45, 1.71 and 1.91 μm, respectively.

[0044] Comparative Example 5 (1) Based on the chemical composition formula: (Ce 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 One of the following is Zr2O7(F3): Rare earth oxides Sc2O3, Dy2O3, Sm2O3, Gd2O3, and Yb2O3, each with a specific chemical composition, are dissolved in nitric acid to form a rare earth nitrate solution; CeCl3 and ZrOCl2 8H2O dissolves in deionized water to form Zr 4+ Solution; (2) Add the solution obtained in step (1) dropwise to ammonia water with pH > 10.0, stirring continuously throughout the process and keeping the pH > 10 to ensure complete formation of flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried powder obtained in step (4) is pre-sintered in a high-temperature sintering furnace at 1050 °C for 5 h; then sintered in the high-temperature sintering furnace at 1350 °C for 6 h to obtain a single-phase high-entropy (Ce) powder. 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2)2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F3) powder.

[0045] Figure 11 This is a single-phase high-entropy (Ce) example in the comparative example. 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 X-ray diffraction pattern of 2Zr2O7(F3) sintered at 1350 °C for 6 h.

[0046] Comparative Example 6 (1) Based on the chemical composition formula: (Ce 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 One of the following is Zr2O7(F3): Rare earth oxides Sc2O3, Dy2O3, Sm2O3, Gd2O3, and Yb2O3, each with a specific chemical composition, are dissolved in nitric acid to form a rare earth nitrate solution; CeCl3 and ZrOCl2 8H2O dissolves in deionized water to form Zr 4+ Solution; (2) Add the solution obtained in step (1) dropwise to ammonia water with pH > 10.0, stirring continuously throughout the process and keeping the pH > 10 to ensure complete formation of flocculent precipitate; (3) Let the precipitate obtained in step (2) stand for 24 hours to allow the material to react fully and allow the flocculated suspended matter to settle. (4) The precipitate obtained in step (3) is first washed repeatedly by centrifugation with deionized water until it is neutral (pH≈7), then washed twice each with ethanol and isopropanol and dried. (5) The dried powder obtained in step (4) is pre-sintered in a high-temperature sintering furnace at 950 °C for 10 h; the sintered powder and the pressed powder are then sintered in a high-temperature sintering furnace at 1600 °C for 10, 30, 50, 70, and 100 h respectively to obtain a dual-phase high-entropy rare earth zirconate thermal barrier coating material with excellent sintering resistance. 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 The average grain sizes of 2Zr2O7(F1) were 4.56, 6.71, 8.46, 10.54, and 11.53 μm, respectively; (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 The average grain sizes of 2Zr2O7(F2) were 5.28, 6.36, 7.46, 8.97, and 9.21 μm, respectively; (Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 The average grain sizes of 2Zr2O7(F3) are 3.65, 4.86, 6.62, 8.41, and 8.84 μm, respectively.

[0047] Figure 12 This is a single-phase high-entropy (Ce) example in the comparative example. 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F1), (Sc 0.1 Ce 0.1 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 )2Zr2O7(F2),(Sc 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2 Statistical results and growth trend of average grain size of 2Zr2O7(F3).

[0048] In Example 1 Figure 1 Compared with Comparative Example 1 Figure 5 X-ray diffraction pattern of biphase high-entropy rare-earth zirconate sintered at 1600 °C for 10 h; from Figure 1 and Figure 5 As can be seen from the above, the thermal barrier coating materials prepared in Example 1 and Comparative Example 1 are both pyrochlore and fluorite dual-phase structures.

[0049] In Example 2 Figure 2 Compared with Comparative Example 2 Figure 6 The graph shows the change in the coefficient of thermal expansion of two-phase high-entropy rare-earth zirconates from room temperature to 1500 °C. Figure 2 and Figure 7 It can be seen that the coefficient of thermal expansion of the dual-phase thermal barrier coating materials prepared in Example 2 and Comparative Example 2 both increase with increasing temperature; In Example 3 Figure 3 Compared with Comparative Example 3 Figure 7 X-ray diffraction pattern of biphase high-entropy rare-earth zirconate sintered at 1350 °C for 6 h; from Figure 3 and Figure 7 It can be seen that the thermal barrier coating materials prepared in Example 3 and Comparative Example 3 are both pyrochlore and fluorite dual-phase structures.

[0050] In Example 3 Figure 4 Compared with Comparative Example 3 Figure 8 Mechanical properties of two-phase high-entropy rare earth zirconates; from Figure 4 and Figure 8 It can be seen that, compared with Comparative Example 4, the elastic modulus (E) of the Ce-doped biphase high-entropy rare-earth zirconate thermal barrier coating material prepared in Example 4 is reduced, and the fracture toughness (K) is also reduced. IC The entropy of Ce increases. The introduction of Ce increases the disorder in the two-phase composition, leading to a higher mixing entropy. On one hand, high entropy causes significant lattice distortion, hindering dislocation slip and crack propagation. On the other hand, the slow diffusion effect caused by high entropy reduces grain size and growth rate. Finer grains increase grain boundaries, hindering dislocation movement, thereby improving the fracture toughness of the material.

[0051] Figure 9 It is in Example 4 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 )2Zr2O7(FPC3) and Comparative Example 4 (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 The average grain size and growth trend of 2Zr2O7(FP3) dual-phase high-entropy rare earth zirconate after sintering at 1600 °C for 10, 30, 50, 70, and 100 h are shown in the figure. Figure 9 As shown, the introduction of Ce element increases the mixing entropy of the components. The slow diffusion effect brought about by high entropy reduces the grain size. Compared with Comparative Example 4, the grain growth rate between 1600 °C and 100 h of sintering is also significantly reduced, thereby improving the sintering resistance of the material and extending the service life of the material.

[0052] Figure 10 In Example 2 (La) 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FPC1), (La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7(FPC2), (La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 )2Zr2O7(FPC3) and Comparative Example 2 (La 0.2 Sm 0.2 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7(FP1), (La0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.2 )2Zr2O7(FP2), (La 0.2 Nd 0.2 Yb 0.2 Lu 0.2 Sc 0.2 A comparison of the thermal expansion coefficients of 2Zr2O7(FP3) dual-phase high-entropy rare-earth zirconate at 1500 °C. Figure 10 As shown in Example 2, due to the large bond length of Ce-O bonds, the introduction of Ce element effectively improves the thermal expansion coefficient of the dual-phase high-entropy rare earth zirconate coating material, which can reduce the difference in thermal expansion coefficient between the coating material and the alloy matrix material, improve the thermal shock resistance of the thermal barrier coating material, and avoid the thermal barrier coating material from peeling off and failing.

[0053] For any points not covered above, existing technologies shall apply.

[0054] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare-earth zirconate thermal barrier coating material, characterized in that, Its chemical formula is (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7、(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7、(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 One of )2Zr2O7.

2. A method for preparing a non-uniform Ce-doped pyrochlore and fluorite dual-phase high-entropy rare-earth zirconate thermal barrier coating material as described in claim 1, characterized in that, Includes the following steps: S1, rare earth source and zirconium source according to (La 0.2 Ce 0.1 Sm 0.1 Dy 0.2 Yb 0.2 Sc 0.2 )2Zr2O7、(La 0.2 Sm 0.2 Yb 0.2 Sc 0.2 Y 0.1 Ce 0.1 )2Zr2O7、(La 0.2 Ce 0.1 Nd 0.1 Yb 0.2 Lu 0.2 Sc 0.2 A solution is prepared by mixing ingredients in a molar ratio of one of the molecular formulas in 2Zr2O7. S2, using the reverse coprecipitation method, the solution obtained in step S1 is added dropwise to ammonia water while continuously stirring; S3, After the flocculent precipitate obtained in step S2 is allowed to stand and age for a period of time, it is then centrifuged, washed, and dried. S4. The dried mixed powder obtained in step S3 is preheated for a period of time to obtain a mixed heat-treated powder. The preheated mixed powder is sintered in a muffle furnace for a period of time to obtain a rare earth zirconate thermal barrier coating powder.

3. The preparation method according to claim 2, characterized in that: During the reverse coprecipitation titration in step S2, ammonia water needs to be continuously added to maintain the pH above 10.

4. The preparation method according to claim 2, characterized in that: In step S3, the settling and aging time shall not be less than 24 hours.

5. The preparation method according to claim 2, characterized in that: In step S3, the generated flocculent precipitate is first washed repeatedly by centrifugation with deionized water until neutral, and then washed twice each with ethanol and isopropanol.

6. The preparation method according to claim 2, characterized in that: In step S4, the preheating temperature is 950~1100°C. The preheating time is 5~10 h.

7. The preparation method according to claim 2, characterized in that: In step S4, sintering is carried out in an air atmosphere in a muffle furnace at a calcination temperature of 1350~1600 ℃ for at least 6 h.

8. The preparation method according to claim 2, characterized in that: The rare earth source includes one or more of rare earth oxides, rare earth chlorides, rare earth nitrates, and rare earth sulfates.

9. The preparation method according to claim 2, characterized in that: The zirconium source includes one or more of zirconium dichloride octahydrate, zirconium nitrate, zirconium sulfate, and zirconium chloride.

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